1. Technical Field
The present disclosure relates to a driving device of a micropump and a microvalve capable of easily realizing control of pump displacement and reducing loss by energizing a shape memory alloy for pump driving only during energizing a shape memory alloy for valve driving arranged in series, in a microfluidic device that drives a pump or a valve, using the shape memory alloy, and a microfluidic device using the driving device.
2. Description of the Related Art
There has been known a microfluidic device as a device that creates a minute flow channel, a reactor vessel, or the like, using fine processing technologies such as a micromachining technology, and that conducts chemical analysis, chemical synthesis, bio experiment or the like. The microfluidic device is also called a μ-TAS or a Labo on a chip, and has been developed. Ordinarily, in the microfluidic device, a supplied liquid such as blood is sent to a reactor provided on the device to perform thermal or chemical reaction processing. Thereafter, the liquid after reaction processing is sent to a detector provided on the device, and a result of the reaction is determined to thereby evaluate the supplied liquid. Therefore, in the microfluidic device, the micropump or the microvalve to control a flow of the liquid is required. As one method of the micropump or the microvalve, there has been a method of deforming a diaphragm provided in the microfluidic device. The diaphragm, when being deformed to push a flow channel, comes to serve as the valve. Moreover, by using a check valve and volume change accompanying reciprocation displacement of the diaphragm, a so-called diaphragm type pump can be configured. For a method for deforming the diaphragm, there have been proposed methods using various actuators such as a piezoelectric actuator, a static actuator, and an electromagnetic actuator, because the actuator to be driven can be freely selected. As one type of the above-described micropump or microvalve, there has been proposed a diaphragm type micropump or microvalve using a shape memory alloy actuator (e.g., refer to PTL 1 and PTL 2). The shape memory alloy actuator uses a phenomenon in which a wire-like shape memory alloy contracts by temperature rise due to energization heating, and extends to an original length by temperature drop due to natural heat dissipation. Using the shape memory alloy actuator enables a micropump or microvalve compact in sizes in directions other than a displacement direction to be configured, which allows the plurality of micropumps or microvalves to be easily arranged on the microfluidic device.